Method and System for Providing Real Time Analyte Sensor Calibration with Retrospective Backfill

ABSTRACT

Provided are methods and apparatus for receiving sensor data from an analyte sensor of a sensor monitoring system, processing the received sensor data with time corresponding calibration data, outputting the processed sensor data, detecting one or more adverse conditions associated with the sensor monitoring system, disabling the output of the sensor data during the adverse condition time period, determining that the one or more detected adverse conditions is no longer present in the sensor monitoring system, retrieving the sensor data during the adverse condition time period, processing the retrieved sensor data during the adverse condition time period, and outputting the processed retrieved sensor data.

RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119(e) to U.S.provisional application No. 61/173,600 filed Apr. 29, 2009, entitled“Method and System for Providing Real Time Analyte Sensor Calibrationwith Retrospective Backfill”, the disclosure of which is incorporated inits entirety by reference for all purposes.

BACKGROUND

Analyte, e.g., glucose monitoring systems including continuous anddiscrete monitoring systems generally include a small, lightweightbattery powered and microprocessor controlled system which is configuredto detect signals proportional to the corresponding measured glucoselevels using an electrometer. RF signals may be used to transmit thecollected data. One aspect of certain analyte monitoring systems includea transcutaneous or subcutaneous analyte sensor configuration which is,for example, at least partially positioned through the skin layer of asubject whose analyte level is to be monitored. The sensor may use a twoor three-electrode (work, reference and counter electrodes)configuration driven by a controlled potential (potentiostat) analogcircuit connected through a contact system.

An analyte sensor may be configured so that a portion thereof is placedunder the skin of the patient so as to contact analyte of the patient,and another portion or segment of the analyte sensor may be incommunication with the transmitter unit. The transmitter unit may beconfigured to transmit the analyte levels detected by the sensor over awireless communication link such as an RF (radio frequency)communication link to a receiver/monitor unit. The receiver/monitor unitmay perform data analysis, among other functions, on the receivedanalyte levels to generate information pertaining to the monitoredanalyte levels.

SUMMARY

Devices and methods for analyte monitoring, e.g., glucose monitoring,and/or therapy management system including, for example, medicationinfusion device are provided. Embodiments include transmittinginformation from a first location to a second, e.g., using a telemetrysystem such as RF telemetry. Systems herein include continuous analytemonitoring systems, discrete analyte monitoring system, and therapymanagement systems.

Embodiments include receiving sensor data from an analyte sensor of asensor monitoring system, processing the received sensor data with timecorresponding calibration data, outputting the processed sensor data,detecting one or more adverse conditions associated with the sensormonitoring system, disabling the output of the sensor data during aadverse condition time period, determining that the one or more detectedadverse conditions is no longer present in the sensor monitoring system,retrieving the sensor data during the adverse condition time period,processing the retrieved sensor data during the adverse condition timeperiod, and outputting the processed retrieved sensor data.

Embodiments include detecting a condition unsuitable for calibration ofan analyte sensor for a predetermined time period, disabling output ofinformation associated with the analyte sensor, determining a successfulcalibration of the analyte sensor, retrieving one or more parametersassociated with the successful calibration, processing sensor dataduring the time period of disabled output of information with the one ormore parameters associated with the successful calibration, anddisplaying the processed sensor data for the time period of disabledinformation output.

Embodiments include an interface configured to receive sensor data, afirst memory configured to store the received sensor data, a processorcoupled to the memory and configured to process the stored sensor data,a second memory coupled to the processor and configured to store theprocessed sensor data, and a display unit coupled to the second memoryand configured to display the processed sensor data, where the processoris further configured to detect a condition unsuitable for calibrationof a sensor for a predetermined time period, disable display ofprocessed sensor data, determine a successful calibration of the sensor,retrieve one or more parameters associated with the successfulcalibration, process the sensor data during the time period of disableddisplay of sensor data with the one or more parameters associated withthe successful calibration, and display the processed sensor data forthe time period of disabled information output.

These and other objects, features and advantages of the presentdisclosure will become more fully apparent from the following detaileddescription of the embodiments, the appended claims and the accompanyingdrawings.

INCORPORATION BY REFERENCE

The following patents, applications and/or publications are incorporatedherein by reference for all purposes: U.S. Pat. Nos. 4,545,382;4,711,245; 5,262,035; 5,262,305; 5,264,104; 5,320,715; 5,509,410;5,543,326; 5,593,852; 5,601,435; 5,628,890; 5,820,551; 5,822,715;5,899,855; 5,918,603; 6,071,391; 6,103,033; 6,120,676; 6,121,009;6,134,461; 6,143,164; 6,144,837; 6,161,095; 6,175,752; 6,270,455;6,284,478; 6,299,757; 6,338,790; 6,377,894; 6,461,496; 6,503,381;6,514,460; 6,514,718; 6,540,891; 6,560,471; 6,579,690; 6,591,125;6,592,745; 6,600,997; 6,605,200; 6,605,201; 6,616,819; 6,618,934;6,650,471; 6,654,625; 6,676,816; 6,730,200; 6,736,957; 6,746,582;6,749,740; 6,764,581; 6,773,671; 6,881,551; 6,893,545; 6,932,892;6,932,894; 6,942,518; 7,167,818; and 7,299,082; U.S. PublishedApplication Nos. 2004/0186365; 2005/0182306; 2007/0056858; 2007/0068807;2007/0227911; 2007/0233013; 2008/0081977; 2008/0161666; and2009/0054748; U.S. patent application Ser. Nos. 11/831,866; 11/831,881;11/831,895; 12/102,839; 12/102,844; 12/102,847; 12/102,855; 12/102,856;12/152,636; 12/152,648; 12/152,650; 12/152,652; 12/152,657; 12/152,662;12/152,670; 12/152,673; 12/363,712; 12/131,012; 12/242,823; 12/363,712;12/393,921; 12/495,709; 12/698,124; 12/699,653; 12/699,844; 12/714,439;12/761,372; and 12/761,387 and U.S. Provisional Application Ser. Nos.61/230,686 and 61/227,967.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of a data monitoring and managementsystem for practicing one or more embodiments of the present disclosure;

FIG. 2 is a block diagram of the transmitter unit of the data monitoringand management system shown in FIG. 1 in accordance with one embodimentof the present disclosure;

FIG. 3 is a block diagram of the receiver/monitor unit of the datamonitoring and management system shown in FIG. 1 in accordance with oneembodiment of the present disclosure;

FIG. 4 illustrates analyte sensor data processing in accordance with oneembodiment of the present disclosure;

FIG. 5 illustrates analyte sensor data processing in accordance with oneembodiment of the present disclosure;

FIG. 6 illustrates backfilling gaps in sensor data in one embodiment ofthe present disclosure; and

FIGS. 7A and 7B illustrate backfill of gaps of a period of uncalibratedsensor data in one embodiment.

DETAILED DESCRIPTION

Before the present disclosure is described in additional detail, it isto be understood that this disclosure is not limited to particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present disclosure will be limited onlyby the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the disclosure. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges is also encompassed within the disclosure, subject to anyspecifically excluded limit in the stated range. Where the stated rangeincludes one or both of the limits, ranges excluding either or both ofthose included limits are also included in the disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present disclosure, the preferredmethods and materials are now described. All publications mentionedherein are incorporated herein by reference to disclose and describe themethods and/or materials in connection with which the publications arecited.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior disclosure.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentdisclosure.

The figures shown herein are not necessarily drawn to scale, with somecomponents and features being exaggerated for clarity.

As described in further detail below, in accordance with the variousembodiments of the present disclosure, there is provided a method andsystem for positioning a controller unit within a transmission range forclose proximity communication, transmitting one or more predefined closeproximity commands, and receiving a response packet in response to thetransmitted one or more predefined close proximity commands. Forexample, in one aspect, close proximity communication includes shortrange wireless communication between communication components ordevices, where the communication range is limited to about 10 inches orless, about 5 inches or less, or about 2 inches or less, or othersuitable, short range or distance between the devices. The closeproximity wireless communication in certain embodiments includes abi-directional communication where a command sending communicationdevice, when positioned within the short communication range or in closeproximity to the command receiving communication device, is configuredto transmit one or more commands to the command receiving communicationdevice (for example, when a user activates or actuates a transmitcommand button or switch). In response, the command receivingcommunication device may be configured to perform one or more routinesassociated with the received command, and/or return or send back aresponse data packet or signal to the command sending communicationdevice. Example of such functions and or commands may include, but notlimited to activation of certain functions or routines such as analyterelated data processing, and the like.

FIG. 1 illustrates a data monitoring and management system such as, forexample, analyte (e.g., glucose) monitoring system 100 in accordancewith one embodiment of the present disclosure. The subject invention isfurther described primarily with respect to a glucose monitoring systemfor convenience and such description is in no way intended to limit thescope of the invention. It is to be understood that the analytemonitoring system may be configured to monitor a variety of analytes,e.g., lactate, and the like.

Analytes that may be monitored include, for example, acetyl choline,amylase, bilirubin, cholesterol, chorionic gonadotropin, creatine kinase(e.g., CK-MB), creatine, DNA, fructosamine, glucose, glutamine, growthhormones, hormones, ketones, lactate, peroxide, prostate-specificantigen, prothrombin, RNA, thyroid stimulating hormone, and troponin.The concentration of drugs, such as, for example, antibiotics (e.g.,gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs ofabuse, theophylline, and warfarin, may also be monitored. More than oneanalyte may be monitored by a single system, e.g. a single analytesensor.

The analyte monitoring system 100 includes a sensor unit 101, a dataprocessing and transmitter unit 102 coupleable to the sensor unit 101,and a primary receiver unit 104 which is configured to communicate withthe data processing and transmitter unit 102 via a bi-directionalcommunication link 103. The primary receiver unit 104 may be furtherconfigured to transmit data to a data processing terminal 105 forevaluating the data received by the primary receiver unit 104. Moreover,the data processing terminal 105 in one embodiment may be configured toreceive data directly from the data processing and transmitter unit 102via a communication link which may optionally be configured forbi-directional communication. Accordingly, data processing andtransmitter unit 102 and/or receiver unit 104 may include a transceiver.

Also shown in FIG. 1 is an optional secondary receiver unit 106 which isoperatively coupled to the communication link and configured to receivedata transmitted from the data processing and transmitter unit 102.Moreover, as shown in the Figure, the secondary receiver unit 106 isconfigured to communicate with the primary receiver unit 104 as well asthe data processing terminal 105. Indeed, the secondary receiver unit106 may be configured for bi-directional wireless communication witheach or one of the primary receiver unit 104 and the data processingterminal 105. As discussed in further detail below, in one embodiment ofthe present disclosure, the secondary receiver unit 106 may beconfigured to include a limited number of functions and features ascompared with the primary receiver unit 104. As such, the secondaryreceiver unit 106 may be configured substantially in a smaller compacthousing or embodied in a device such as a wrist watch, pager, mobilephone, PDA, for example. Alternatively, the secondary receiver unit 106may be configured with the same or substantially similar functionalityas the primary receiver unit 104. The receiver unit may be configured tobe used in conjunction with a docking cradle unit, for example for oneor more of the following or other functions: placement by bedside, forre-charging, for data management, for night time monitoring, and/orbi-directional communication device.

In one aspect sensor unit 101 may include two or more sensors, eachconfigured to communicate with data processing and transmitter unit 102.Furthermore, while only one, data processing and transmitter unit 102,communication link 103, and data processing terminal 105 are shown inthe embodiment of the analyte monitoring system 100 illustrated inFIG. 1. However, it will be appreciated by one of ordinary skill in theart that the analyte monitoring system 100 may include one or moresensors, multiple transmitter units 102, communication links 103, anddata processing terminals 105. Moreover, within the scope of the presentdisclosure, the analyte monitoring system 100 may be a continuousmonitoring system, or semi-continuous, or a discrete monitoring system.In a multi-component environment, each device is configured to beuniquely identified by each of the other devices in the system so thatcommunication conflict is readily resolved between the variouscomponents within the analyte monitoring system 100.

In one embodiment of the present disclosure, the sensor unit 101 isphysically positioned in or on the body of a user whose analyte level isbeing monitored. The sensor unit 101 may be configured to continuouslysample the analyte level of the user and convert the sampled analytelevel into a corresponding data signal for transmission by the dataprocessing and transmitter unit 102. In certain embodiments, the dataprocessing and transmitter unit 102 may be physically coupled to thesensor unit 101 so that both devices are integrated in a single housingand positioned on the user's body. The data processing and transmitterunit 102 may perform data processing such as filtering and encoding ondata signals and/or other functions, each of which corresponds to asampled analyte level of the user, and in any event data processing andtransmitter unit 102 transmits analyte information to the primaryreceiver unit 104 via the communication link 103. Examples of suchintegrated sensor and transmitter units can be found in, among others,U.S. patent application Ser. No. 12/698,124, incorporated herein byreference.

In one embodiment, the analyte monitoring system 100 is configured as aone-way RF communication path from the data processing and transmitterunit 102 to the primary receiver unit 104. In such embodiment, the dataprocessing and transmitter unit 102 transmits the sampled data signalsreceived from the sensor unit 101 without acknowledgement from theprimary receiver unit 104 that the transmitted sampled data signals havebeen received. For example, the data processing and transmitter unit 102may be configured to transmit the encoded sampled data signals at afixed rate (e.g., at one minute intervals) after the completion of theinitial power on procedure. Likewise, the primary receiver unit 104 maybe configured to detect such transmitted encoded sampled data signals atpredetermined time intervals. Alternatively, the analyte monitoringsystem 100 may be configured with a bi-directional RF (or otherwise)communication between the data processing and transmitter unit 102 andthe primary receiver unit 104.

Additionally, in one aspect, the primary receiver unit 104 may includetwo sections. The first section is an analog interface section that isconfigured to communicate with the data processing and transmitter unit102 via the communication link 103. In one embodiment, the analoginterface section may include an RF receiver and an antenna forreceiving and amplifying the data signals from the data processing andtransmitter unit 102, which are thereafter, demodulated with a localoscillator and filtered through a band-pass filter. The second sectionof the primary receiver unit 104 is a data processing section which isconfigured to process the data signals received from the data processingand transmitter unit 102 such as by performing data decoding, errordetection and correction, data clock generation, and data bit recovery.

In operation, upon completing the power-on procedure, the primaryreceiver unit 104 is configured to detect the presence of the dataprocessing and transmitter unit 102 within its range based on, forexample, the strength of the detected data signals received from thedata processing and transmitter unit 102 and/or a predeterminedtransmitter identification information. Upon successful synchronizationwith the corresponding data processing and transmitter unit 102, theprimary receiver unit 104 is configured to begin receiving from the dataprocessing and transmitter unit 102 data signals corresponding to theuser's detected analyte level. More specifically, the primary receiverunit 104 in one embodiment is configured to perform synchronized timehopping with the corresponding synchronized data processing andtransmitter unit 102 via the communication link 103 to obtain the user'sdetected analyte level.

Referring again to FIG. 1, the data processing terminal 105 may includea personal computer, a portable computer such as a laptop or a handhelddevice (e.g., personal digital assistants (PDAs)), and the like, each ofwhich may be configured for data communication with the receiver via awired or a wireless connection. Additionally, the data processingterminal 105 may further be connected to a data network (not shown) forstoring, retrieving and updating data corresponding to the detectedanalyte level of the user.

Within the scope of the present disclosure, the data processing terminal105 may include an infusion device such as an insulin infusion pump(external or implantable) or the like, which may be configured toadminister insulin to patients, and which may be configured tocommunicate with the receiver unit 104 for receiving, among others, themeasured analyte level. Alternatively, the receiver unit 104 may beconfigured to integrate or otherwise couple to an infusion devicetherein so that the receiver unit 104 is configured to administerinsulin therapy to patients, for example, for administering andmodifying basal profiles, as well as for determining appropriate bolusesfor administration based on, among others, the detected analyte levelsreceived from the data processing and transmitter unit 102.

Additionally, the data processing and transmitter unit 102, the primaryreceiver unit 104 and the data processing terminal 105 may each beconfigured for bi-directional wireless communication such that each ofthe data processing and transmitter unit 102, the primary receiver unit104 and the data processing terminal 105 may be configured tocommunicate (that is, transmit data to and receive data from) with eachother via the wireless communication link 103. More specifically, thedata processing terminal 105 may in one embodiment be configured toreceive data directly from the data processing and transmitter unit 102via the communication link 103, where the communication link 103, asdescribed above, may be configured for bi-directional communication.

In this embodiment, the data processing terminal 105 which may includean insulin pump, may be configured to receive the analyte signals fromthe data processing and transmitter unit 102, and thus, incorporate thefunctions of the receiver 104 including data processing for managing thepatient's insulin therapy and analyte monitoring. In one embodiment, thecommunication link 103 may include one or more of an RF communicationprotocol, an infrared communication protocol, a Bluetooth® enabledcommunication protocol, an 802.11x wireless communication protocol, oran equivalent wireless communication protocol which would allow secure,wireless communication of several units (for example, per HIPPArequirements) while avoiding potential data collision and interference.

FIG. 2 is a block diagram of the transmitter of the data monitoring anddetection system shown in FIG. 1 in accordance with one embodiment ofthe present disclosure. Referring to the Figure, the data processing andtransmitter unit 102 in one embodiment includes an analog interface 201configured to communicate with the sensor unit 101 (FIG. 1), a userinput 202, and a temperature measurement section 203, each of which isoperatively coupled to a transmitter processor 204 such as a centralprocessing unit (CPU). As can be seen from FIG. 2, there are providedfour contacts, three of which are electrodes—work electrode (W) 210,guard contact (G) 211, reference electrode (R) 212, and counterelectrode (C) 213, each operatively coupled to the analog interface 201of the data processing and transmitter unit 102 for connection to thesensor unit 101 (FIG. 1). In one embodiment, each of the work electrode(W) 210, guard contact (G) 211, reference electrode (R) 212, and counterelectrode (C) 213 may be made using a conductive material that is eitherprinted or etched or ablated, for example, such as carbon which may beprinted, or a metal such as a metal foil (e.g., gold) or the like, whichmay be etched or ablated or otherwise processed to provide one or moreelectrodes. Fewer or greater electrodes and/or contact may be providedin certain embodiments.

Further shown in FIG. 2 are a transmitter serial communication section205 and an RF transmitter 206, each of which is also operatively coupledto the transmitter processor 204. Moreover, a power supply 207 such as abattery is also provided in the data processing and transmitter unit 102to provide the necessary power for the data processing and transmitterunit 102. In certain embodiments, the power supply 207 also provides thepower necessary to power the sensor 101. In other embodiments, thesensor is a self-powered sensor, such as the sensor described in U.S.patent application Ser. No. 12/393,921, incorporated herein byreference. Additionally, as can be seen from the Figure, clock 208 isprovided to, among others, supply real time information to thetransmitter processor 204.

In one embodiment, a unidirectional input path is established from thesensor unit 101 (FIG. 1) and/or manufacturing and testing equipment tothe analog interface 201 of the data processing and transmitter unit102, while a unidirectional output is established from the output of theRF transmitter 206 of the data processing and transmitter unit 102 fortransmission to the primary receiver unit 104. In this manner, a datapath is shown in FIG. 2 between the aforementioned unidirectional inputand output via a dedicated link 209 from the analog interface 201 toserial communication section 205, thereafter to the processor 204, andthen to the RF transmitter 206. As such, in one embodiment, via the datapath described above, the data processing and transmitter unit 102 isconfigured to transmit to the primary receiver unit 104 (FIG. 1), viathe communication link 103 (FIG. 1), processed and encoded data signalsreceived from the sensor unit 101 (FIG. 1). Additionally, theunidirectional communication data path between the analog interface 201and the RF transmitter 206 discussed above allows for the configurationof the data processing and transmitter unit 102 for operation uponcompletion of the manufacturing process as well as for directcommunication for diagnostic and testing purposes.

As discussed above, the transmitter processor 204 is configured totransmit control signals to the various sections of the data processingand transmitter unit 102 during the operation of the data processing andtransmitter unit 102. In one embodiment, the transmitter processor 204also includes a memory (not shown) for storing data such as theidentification information for the data processing and transmitter unit102, as well as the data signals received from the sensor unit 101. Thestored information may be retrieved and processed for transmission tothe primary receiver unit 104 under the control of the transmitterprocessor 204. Furthermore, the power supply 207 may include acommercially available battery, which may be a rechargeable battery.

In certain embodiments, the data processing and transmitter unit 102 isalso configured such that the power supply section 207 is capable ofproviding power to the transmitter for a minimum of about three monthsof continuous operation, e.g., after having been stored for abouteighteen months such as stored in a low-power (non-operating) mode. Inone embodiment, this may be achieved by the transmitter processor 204operating in low power modes in the non-operating state, for example,drawing no more than approximately 1 μA of current. Indeed, in oneembodiment, a step during the manufacturing process of the dataprocessing and transmitter unit 102 may place the data processing andtransmitter unit 102 in the lower power, non-operating state (i.e.,post-manufacture sleep mode). In this manner, the shelf life of the dataprocessing and transmitter unit 102 may be significantly improved.Moreover, as shown in FIG. 2, while the power supply unit 207 is shownas coupled to the processor 204, and as such, the processor 204 isconfigured to provide control of the power supply unit 207, it should benoted that within the scope of the present disclosure, the power supplyunit 207 is configured to provide the necessary power to each of thecomponents of the data processing and transmitter unit 102 shown in FIG.2.

Referring back to FIG. 2, the power supply section 207 of the dataprocessing and transmitter unit 102 in one embodiment may include arechargeable battery unit that may be recharged by a separate powersupply recharging unit (for example, provided in the receiver unit 104)so that the data processing and transmitter unit 102 may be powered fora longer period of usage time. Moreover, in one embodiment, the dataprocessing and transmitter unit 102 may be configured without a batteryin the power supply section 207, in which case the data processing andtransmitter unit 102 may be configured to receive power from an externalpower supply source (for example, a battery) as discussed in furtherdetail below.

Referring yet again to FIG. 2, the temperature measurement section 203of the data processing and transmitter unit 102 is configured to monitorthe temperature of the skin near the sensor insertion site. Thetemperature reading is used to adjust the analyte readings obtained fromthe analog interface 201. In certain embodiments, the RF transmitter 206of the transmitter unit 102 may be configured for operation in thefrequency band of approximately 315 MHz to approximately 322 MHz, forexample, in the United States. In certain embodiments, the RFtransmitter 206 of the transmitter unit 102 may be configured foroperation in the frequency band of approximately 400 MHz toapproximately 470 MHz. Further, in one embodiment, the RF transmitter206 is configured to modulate the carrier frequency by performingFrequency Shift Keying and Manchester encoding. In one embodiment, thedata transmission rate is about 19,200 symbols per second, with aminimum transmission range for communication with the primary receiverunit 104.

Referring yet again to FIG. 2, also shown is a leak detection circuit214 coupled to the guard electrode (G) 211 and the processor 204 in thetransmitter unit 102 of the data monitoring and management system 100.The leak detection circuit 214 in accordance with one embodiment of thepresent disclosure may be configured to detect leakage current in thesensor unit 101 to determine whether the measured sensor data arecorrupt or whether the measured data from the sensor 101 is accurate.Exemplary analyte systems that may be employed are described in, forexample, U.S. Pat. Nos. 6,134,461, 6,175,752, 6,121,611, 6,560,471,6,746,582, and elsewhere, the disclosure of each of which areincorporated by reference for all purposes.

FIG. 3 is a block diagram of the receiver/monitor unit of the datamonitoring and management system shown in FIG. 1 in accordance with oneembodiment of the present disclosure. Referring to FIG. 3, the primaryreceiver unit 104 includes an analyte test strip, e.g., blood glucosetest strip, interface 301, an RF receiver 302, an input 303, atemperature monitor section 304, and a clock 305, each of which isoperatively coupled to a receiver processor 307. As can be further seenfrom the Figure, the primary receiver unit 104 also includes a powersupply 306 operatively coupled to a power conversion and monitoringsection 308. Further, the power conversion and monitoring section 308 isalso coupled to the receiver processor 307. Moreover, also shown are areceiver serial communication section 309, and an output 310, eachoperatively coupled to the receiver processor 307.

In one embodiment, the test strip interface 301 includes a glucose leveltesting portion to receive a manual insertion of a glucose test strip,and thereby determine and display the glucose level of the test strip onthe output 310 of the primary receiver unit 104. This manual testing ofglucose may be used to calibrate the sensor unit 101 or otherwise. TheRF receiver 302 is configured to communicate, via the communication link103 (FIG. 1) with the RF transmitter 206 of the transmitter unit 102, toreceive encoded data signals from the transmitter unit 102 for, amongothers, signal mixing, demodulation, and other data processing. Theinput 303 of the primary receiver unit 104 is configured to allow theuser to enter information into the primary receiver unit 104 as needed.In one aspect, the input 303 may include one or more keys of a keypad, atouch-sensitive screen, or a voice-activated input command unit. Thetemperature monitor section 304 is configured to provide temperatureinformation of the primary receiver unit 104 to the receiver processor307, while the clock 305 provides, among others, real time informationto the receiver processor 307.

Each of the various components of the primary receiver unit 104 shown inFIG. 3 is powered by the power supply 306 which, in one embodiment,includes a battery. Furthermore, the power conversion and monitoringsection 308 is configured to monitor the power usage by the variouscomponents in the primary receiver unit 104 for effective powermanagement and to alert the user, for example, in the event of powerusage which renders the primary receiver unit 104 in sub-optimaloperating conditions. An example of such sub-optimal operating conditionmay include, for example, operating the vibration output mode (asdiscussed below) for a period of time thus substantially draining thepower supply 306 while the processor 307 (thus, the primary receiverunit 104) is turned on. Moreover, the power conversion and monitoringsection 308 may additionally be configured to include a reverse polarityprotection circuit such as a field effect transistor (FET) configured asa battery activated switch.

The serial communication section 309 in the primary receiver unit 104 isconfigured to provide a bi-directional communication path from thetesting and/or manufacturing equipment for, among others,initialization, testing, and configuration of the primary receiver unit104. Serial communication section 104 can also be used to upload data toa computer, such as time-stamped blood glucose data. The communicationlink with an external device (not shown) can be made, for example, bycable, infrared (IR) or RF link. The output 310 of the primary receiverunit 104 is configured to provide, among others, a graphical userinterface (GUI) such as a liquid crystal display (LCD) for displayinginformation. Additionally, the output 310 may also include an integratedspeaker for outputting audible signals as well as to provide vibrationoutput as commonly found in handheld electronic devices, such as mobiletelephones presently available. In a further embodiment, the primaryreceiver unit 104 also includes an electro-luminescent lamp configuredto provide backlighting to the output 310 for output visual display indark ambient surroundings.

Referring back to FIG. 3, the primary receiver unit 104 in oneembodiment may also include a storage section such as a programmable,non-volatile memory device as part of the processor 307, or providedseparately in the primary receiver unit 104, operatively coupled to theprocessor 307. The processor 307 may be configured to synchronize with atransmitter, e.g., using Manchester decoding or the like, as well aserror detection and correction upon the encoded data signals receivedfrom the transmitter unit 102 via the communication link 103.

Periodic calibration of the sensor unit 101 (FIG. 1) of an analytemonitoring system 100, in some embodiments, may be required for accuratecalculation of a user's analyte level. Calibration, in some aspects, isused to ensure the analyte related data signals received at atransmitter unit 102 (and further transmitted to a receiver unit, suchas the primary receiver unit 104) are correctly converted tocorresponding analyte levels. Exemplary calibration protocols, routinesand techniques are described, for example, in U.S. Pat. No. 7,299,082,U.S. patent application Ser. No. 11/537,991 filed Oct. 2, 2006, U.S.patent application Ser. No. 12/363,706 filed Jan. 30, 2009 and in U.S.patent application Ser. No. 12/363,712 filed Jan. 30, 2009, thedisclosures of each of which are herein incorporated by reference forall purposes.

There are time periods where the sensor characteristics or the user'sphysiological condition renders the condition unsuitable for a sensorcalibration event. For example, the sensor may be configured forperiodic calibration, such as, after 2 hours after insertion, 10 hoursafter insertion, 12 hours after insertion, 24 hours after insertion, 48hours after insertion, or 72 hours after insertion, or one or morecombinations thereof. If a predetermined calibration event is triggeredbut a successful calibration does not result, after a certain timeperiod (for example, a predetermined grace period during which tocalibrate), the receiver unit may no longer display the monitored andprocessed glucose information.

Other conditions may also result in rendering the condition unsuitablefor sensor calibration including, but not limited to, detection of afailure mode of a sensor, sensor data values being outside apredetermined range, rate of change of sensor data values being above apredetermined threshold, a temperature measurement outside apredetermined range, or any combination thereof.

FIG. 4 illustrates analyte sensor data processing in accordance with oneembodiment of the present disclosure. Referring to FIG. 4, a transmitterunit 102 (FIG. 1) in operational contact with a sensor 101 receivesanalyte related sensor data (410) corresponding to a measured level of abiological fluid of the user. For example, the sensor 101 (FIG. 1) maybe an analyte sensor configured to detect and measure the concentrationof an analyte in a biological fluid, such as the blood of a user. Uponreceipt of the analyte related sensor data, the transmitter unit 102further transmits the analyte related sensor data to a receiver unit,such as primary receiver unit 104 (FIG. 1). It is to be noted that thereference to analyte related sensor data herein and throughoutspecification includes, for example, current signal received from theanalyte sensor, as well as the current signal which has undergone apredetermined data processing routines including, for example,filtering, clipping, digitizing, and/or encoding, and/or any otherfurther processing and/or conditioning. In one aspect, the primaryreceiver unit 104 determines whether the sensor is calibrated and is inacceptable condition for further data processing (420). When sensorrelated conditions are unsuitable for calibration, the analyte relatedsensor data is stored (450) in a memory, for example, in the primaryreceiver unit 104.

Referring still to FIG. 4, if the sensor data is calibrated and incondition for further data processing, the sensor data is furtherprocessed (430) and output for display (440) to a user on a display unit310 (FIG. 3) of the primary receiver unit 104. In one embodiment, thedisplay of the processed sensor data comprises a graphicalrepresentation of the processed sensor data. In other embodiments, theprocessed sensor data may be displayed as numerical values, visualindicators, auditory outputs, or combinations thereof. In one aspect,the processing routine described in conjunction with FIG. 4 is performedor executed in, for example, the transmitter unit 102, the secondaryreceiver unit 106 (FIG. 1), or the data processing terminal 105 (FIG. 1)of the analyte monitoring system 100 (FIG. 1) based on analyte datareceived from the sensor 101.

FIG. 5 illustrates analyte sensor data processing in accordance with oneembodiment of the present disclosure. Referring to FIG. 5, in oneembodiment, transmitter unit 102 (FIG. 1) receives analyte relatedsensor data (510) from a sensor 101 (FIG. 1). Upon receipt of theanalyte related sensor data, the transmitter unit 102 transmits theanalyte related sensor data (or processed, digitized, and/or filteredsignals) to the primary receiver unit 104 (FIG. 1). The primary receiverunit 104 is configured to determine if calibration of the sensor data issuitable—that is, whether the conditions necessary for sensorcalibration are met (520).

Still referring to FIG. 5, if it is determined that the sensor 101 isnot calibrated or calibration condition for calibrating the sensor 101is not met, in one aspect, the primary receiver unit stores the analyterelated sensor data in a memory (550) and temporarily disables displayof the sensor data (560) to the user (for example, if a calibrationevent has not occurred and the calibration grace period has expired). Onthe other hand, if the sensor 101 is calibrated, the sensor data isprocessed (530) by the primary receiver unit 104 and the processedsensor data is output to the user (540), for example via a display unit310 (FIG. 3) of the primary receiver unit 104. In one aspect, theprocessing routine described in conjunction with FIG. 5 is performed orexecuted in, for example, the transmitter unit 102, the secondaryreceiver unit 106, or the data processing terminal 105 of the analytemonitoring system 100 based on analyte data received from the sensor 101(FIG. 1).

In one aspect, the display or output of processed sensor data may bedisabled if a required calibration event is unsuccessful over apermitted time period (for example, including a predetermined graceperiod measured from the scheduled calibration). Thereafter, uponsuccessful calibration, the system resumes display of the processed andcalibrated analyte sensor data. However, there may be a time period or agap in the output display during which the necessary calibration did notoccur in a timely manner. For example, as shown in FIG. 7A, if sensordata is displayed as a graphical display, during time periods where theanalyte monitoring system 100 was not properly calibrated, analyterelated sensor data was not processed and/or displayed, resulting in agap in the graphical display.

FIG. 6 illustrates backfilling gaps in sensor data in one embodiment ofthe present disclosure. Referring to FIG. 6, when a scheduledcalibration event fails and the associated grace period for calibrationdoes not occur, the output display of the processed, calibrated sensordata is disabled (610). Referring to FIG. 6, once the system recoversafter a successful calibration event, the calibrated sensor data is onceagain displayed (and stored). Furthermore, in one aspect, based on theparameters associated with the successful calibration, the previouslyunprocessed data during the display time out period may be retrieved(for example, the previously stored analyte related sensor signalsduring this period) and processed using calibration data, such as asensitivity ratio for conversion of analyte related sensor data toanalyte levels. For example, in one aspect, the subset of analyterelated sensor data that were previously unprocessed or uncalibrated dueto unsuccessful contemporaneous calibration may be processed using, forexample, calibration data such as the sensitivity ratio determined fromthe most recent successful calibration event, and thereafter, the gap inoutput display illustrating the processed and calibrated signals may befilled.

In one aspect, once successful calibration of the sensor data occurs,the calibration parameters from this calibration event may be used toprocess the sensor data during the period of disabled output or display(620). Upon successful processing of the sensor data during the periodof disabled output, the processed sensor data during this time period isbackfilled, or the gap in the processed continuous sensor data arefilled in the display (630). By way of an example, FIGS. 7A and 7Billustrate the replacement of a period of unprocessed sensor data withcorresponding backfilled processed sensor data, in one embodiment.

In one embodiment, the backfilled processed sensor data is displayedimmediately upon calculation. In another embodiment, the backfilledprocessed sensor data is not displayed immediately, but rather, afterwaiting a predetermined period of time. The backfilled processed sensordata may not be displayed immediately to avoid possible unnecessary orincorrect action by a user in response to the backfilled processedsensor data. In this manner, in one aspect, the user or a healthcareprovider may be provided with a continuous set of analyte data from theanalyte monitoring system without any gaps in the processed signals forfurther analysis and/or therapy management.

In this manner, in accordance with the embodiments of the presentdisclosure, gaps in monitored analyte levels using an analyte monitoringsystem due to, for example, inability to promptly calibrate the sensor,system malfunction, sensor dislodging, signal errors associated with thesensor, transmitter unit, receiver unit, and the like, or any othervariables or parameters that result in the inability of the analytemonitoring system to display or output the real-time monitored analytelevel, may be retrospectively filled or reprocessed so that the data gapis closed and the continuously monitored analyte level does not have anyor substantially missing data. That is, in embodiments of the presentdisclosure, upon correction or rectification of the condition orconditions/parameters which resulted in the analyte monitoring systemdisabling the output results associated with the monitored real timeanalyte levels, the parameters associated with the correction orrectification may be used to retrospectively correct or process data orsignals so that the missing gaps in analyte related data may beprocessed and backfilled.

In this manner, advantageously, in aspects of the present disclosure,additional robustness may be provided to the user and/or the healthcareprovider to improve therapy or health management decisions.

In one embodiment, a method may include receiving sensor data from ananalyte sensor of a sensor monitoring system, processing the receivedsensor data with time corresponding calibration data, outputting theprocessed sensor data, detecting one or more adverse conditionsassociated with the sensor monitoring system, disabling the output ofthe sensor data during an adverse condition time period, determiningthat the one or more detected adverse conditions is no longer present inthe sensor monitoring system, retrieving the sensor data during theadverse condition time period, processing the retrieved sensor dataduring the adverse condition time period, and outputting the processedretrieved sensor data.

In one aspect, outputting the processed sensor data may includedisplaying the sensor data in one or more of a graphical, numerical,pictorial, audible, vibratory, or one or more combinations thereof.

The one or more detected adverse conditions may include one or more of asensor instability condition, a calibration failure condition, or amonitoring system failure condition.

The sensor instability condition may include one or more of an earlysignal attenuation condition of the sensor, sensor misposition error,sensor communication error, temperature measurement outside apredetermined range, or a combination thereof.

The calibration failure condition may include one or more of an analytelevel exceeding a predetermined threshold, a rate of change of analytelevel exceeding a predetermined threshold, a signal error associatedwith the reference data, a data unavailability condition, or acombination thereof.

Furthermore, the method may include storing the processed sensor datawith the associated time information based on the analyte leveldetection time by the sensor.

In another embodiment, a method may include detecting a conditionunsuitable for calibration of an analyte sensor for a predetermined timeperiod, disabling output of information associated with the analytesensor, determining a successful calibration of the analyte sensor,retrieving one or more parameters associated with the successfulcalibration, processing sensor data during the time period of disabledoutput of information with the one or more parameters associated withthe successful calibration, and displaying the processed sensor data forthe time period of disabled information output.

The sensor data may be analyte concentration data.

The analyte concentration data may include blood glucose concentrationdata.

The sensor data may be processed in substantially real-time.

The condition unsuitable for calibration may include one or more of afailure mode of a sensor, sensor data outside a predetermined acceptablerange, a rate of change of sensor data above a predetermined level, arequirement for calibration of a sensor, a temperature measurementoutside a predetermined range, or any combination thereof.

The processed sensor data for the time period of disabled informationoutput may be displayed substantially immediately upon processing.

The processed sensor data for the time period of disabled informationoutput may be displayed only after waiting a predetermined period oftime.

In another embodiment, an apparatus may include an interface configuredto receive sensor data, a first memory configured to store the receivedsensor data, a processor coupled to the memory and configured to processthe stored sensor data, a second memory coupled to the processor andconfigured to store the processed sensor data, and a display unitcoupled to the second memory and configured to display the processedsensor data, wherein the processor is further configured to detect acondition unsuitable for calibration of a sensor for a predeterminedtime period, disable display of processed sensor data, determine asuccessful calibration of the sensor, retrieve one or more parametersassociated with the successful calibration, process the sensor dataduring the time period of disabled display of sensor data with the oneor more parameters associated with the successful calibration, anddisplay the processed sensor data for the time period of disabledinformation output.

The sensor may be an analyte sensor.

The analyte sensor may be a glucose sensor.

The sensor data may correspond to analyte concentration data.

The analyte concentration data may include blood glucose concentrationdata.

Furthermore, the apparatus may be configured to process and display thesensor data substantially in real-time.

In one aspect, the condition unsuitable for calibration may include oneor more of a failure mode of a sensor, sensor data outside apredetermined acceptable range, a rate of change of sensor data above apredetermined level, a requirement for calibration of a sensor, atemperature measurement outside a predetermined range, or anycombination thereof.

The display unit may be configured to display the processed sensor datafor the time period of disabled information output substantiallyimmediately upon processing the sensor data.

The display unit may be configured to display the processed sensor datafor the time period of disabled information output only after waiting apredetermined period of time.

Various other modifications and alterations in the structure and methodof operation of this invention will be apparent to those skilled in theart without departing from the scope and spirit of the invention.Although the invention has been described in connection with specificpreferred embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiments. It isintended that the following claims define the scope of the presentdisclosure and that structures and methods within the scope of theseclaims and their equivalents be covered thereby.

1. A method, comprising: receiving sensor data from an analyte sensor ofa sensor monitoring system; processing the received sensor data withtime corresponding calibration data; outputting the processed sensordata; detecting one or more adverse conditions associated with thesensor monitoring system; disabling the output of the sensor data duringan adverse condition time period; determining that the one or moredetected adverse conditions is no longer present in the sensormonitoring system; retrieving the sensor data during the adversecondition time period; processing the retrieved sensor data during theadverse condition time period; and outputting the processed retrievedsensor data.
 2. The method of claim 1, wherein outputting the processedsensor data includes displaying the sensor data in one or more of agraphical, numerical, pictorial, audible, vibratory, or one or morecombinations thereof.
 3. The method of claim 1, wherein the one or moredetected adverse conditions includes one or more of a sensor instabilitycondition, a calibration failure condition, or a monitoring systemfailure condition.
 4. The method of claim 3, wherein the sensorinstability condition includes one or more of an early signalattenuation condition of the sensor, sensor mis-position error, sensorcommunication error, temperature measurement outside a predeterminedrange, or a combination thereof.
 5. The method of claim 3, wherein thecalibration failure condition includes one or more of an analyte levelexceeding a predetermined threshold, a rate of change of analyte levelexceeding a predetermined threshold, a signal error associated with thereference data, a data unavailability condition, or a combinationthereof.
 6. The method of claim 1 including storing the processed sensordata with the associated time information based on the analyte leveldetection time by the sensor.
 7. A method, comprising: detecting acondition unsuitable for calibration of an analyte sensor for apredetermined time period; disabling output of information associatedwith the analyte sensor; determining a successful calibration of theanalyte sensor; retrieving one or more parameters associated with thesuccessful calibration; processing sensor data during the time period ofdisabled output of information with the one or more parametersassociated with the successful calibration; and displaying the processedsensor data for the time period of disabled information output.
 8. Themethod of claim 7, wherein the sensor data is analyte concentrationdata.
 9. The method of claim 8, wherein the analyte concentration dataincludes blood glucose concentration data.
 10. The method of claim 7,wherein the sensor data is processed in substantially real-time.
 11. Themethod of claim 7, wherein the condition unsuitable for calibrationincludes one or more of a failure mode of a sensor, sensor data outsidea predetermined acceptable range, a rate of change of sensor data abovea predetermined level, a requirement for calibration of a sensor, atemperature measurement outside a predetermined range, or anycombination thereof.
 12. The method of claim 7, wherein the processedsensor data for the time period of disabled information output isdisplayed substantially immediately upon processing.
 13. The method ofclaim 7, wherein the processed sensor data for the time period ofdisabled information output is displayed only after waiting apredetermined period of time.
 14. An apparatus, comprising: an interfaceconfigured to receive sensor data; a first memory configured to storethe received sensor data; a processor coupled to the memory andconfigured to process the stored sensor data; a second memory coupled tothe processor and configured to store the processed sensor data; and adisplay unit coupled to the second memory and configured to display theprocessed sensor data; wherein the processor is further configured to:detect a condition unsuitable for calibration of a sensor for apredetermined time period; disable display of processed sensor data;determine a successful calibration of the sensor; retrieve one or moreparameters associated with the successful calibration; process thesensor data during the time period of disabled display of sensor datawith the one or more parameters associated with the successfulcalibration; and display the processed sensor data for the time periodof disabled information output.
 15. The apparatus of claim 14, whereinthe sensor is an analyte sensor.
 16. The apparatus of claim 15, whereinthe analyte sensor is a glucose sensor.
 17. The apparatus of claim 15,wherein the sensor data corresponds to analyte concentration data. 18.The apparatus of claim 17, wherein the analyte concentration dataincludes blood glucose concentration data.
 19. The apparatus of claim 14configured to process and display the sensor data substantially inreal-time.
 20. The apparatus of claim 14, wherein the conditionunsuitable for calibration includes one or more of a failure mode of asensor, sensor data outside a predetermined acceptable range, a rate ofchange of sensor data above a predetermined level, a requirement forcalibration of a sensor, a temperature measurement outside apredetermined range, or any combination thereof.
 21. The apparatus ofclaim 14, wherein the display unit is configured to display theprocessed sensor data for the time period of disabled information outputsubstantially immediately upon processing the sensor data.
 22. Theapparatus of claim 14, wherein the display unit is configured to displaythe processed sensor data for the time period of disabled informationoutput only after waiting a predetermined period of time.